Planting specific vegetables together can increase their health and yield.
WHAT IS COMPANION PLANTING?BENEFITS OF COMPANION PLANTSIMPORTANCE FOR RAISED BEDSCOMMON FAVORITESCOMBINATIONS TO AVOIDTOP RECOMMENDATIONS
The idea of companion planting is a simple one: take two or more varieties known to grow well together and plant them in close proximity—then enjoy the results. But how do you know what works and what doesn’t?
What is companion planting?
Have you ever heard the phrase ‘carrots love tomatoes’? That old saying refers to the idea that planting these two well-loved vegetables together will often increase the yield of both—making your plants happier, healthier, and stronger.
Understanding how companion plants work together can help you tackle some common gardening problems.
The idea that certain crops work symbiotically to increase yields has been around as long as gardeners. More recently, scientists have studied the phenomenon to try and determine what is actually taking place when plants thrive together. What they’ve discovered is that companion planting can work in the following ways:
- Protecting and shielding crops: More delicate plants can benefit from the presence of hardier varieties, which can provide protection from sun, wind, and heavy rains when planted nearby.
- Improving pollination: Some plants with showy blooms, powerful fragrances, or other attractants can draw pollinating insects to plants in the same vicinity that also require pollination. When plants attract beneficial insects, it helps crops thrive.
- Trapping and luring pests: Planting varieties that attract pests away from the garden can lure pests away from tasty, preferred vegetables and other prized plants. This is called “trap cropping.”
- Repelling pests: Many plants produce substances in their leaves and roots that naturally repel common pests.
- Enriching the soil: Some plants introduce essential nutrients back into the soil as they break down or fix nitrogen from the atmosphere.
Benefits of planting companion crops
In addition to increasing the yield of your harvest, the benefits of companion planting include the following:
Less reliance on chemical pesticides
Companion planting is a form of integrated pest management that helps control pests without harmful chemicals.
Improved flavor
When sown in a vegetable bed, some aromatic herbs will improve the taste of certain vegetables making them great companions.
More biodiversity
Planting a mix of varieties together mimics the diversity found in nature. Avoiding monoculture means reducing the impacts from pests and diseases that prey on a single plant family. It also means providing a haven for the beneficial insects we want in the garden.
Why is companion planting important for raised garden beds?
While raised garden beds are neat, efficient, and easy to tend, they group plants into a confined space, which presents both challenges and opportunities. Choosing the best bedfellows for this space is an important step towards getting the best yield for your crops.
Other important considerations
As you read the recommendations below, keep in mind the unique factors that affect your garden. Are there particular pests you’d like to address? Does your soil have particular needs? Is your garden located in an area with wet weather or hot, drying sun that may affect the plants you hope to grow? Are you looking to solve issues in a greenhouse or polytunnel?
Knowing the problems you want to solve can help you target the best companion plants for your raised garden.
Companion planting favorites
The following companion plantings can work well in almost any garden.
Plants that attract pollinators
The following plants are known to attract pollinators to your vegetable garden. Plant nearby or adjacent to your fruit and vegetable beds for maximum benefit.
Flowering native plants are often attractive to pollinators because they are familiar.
Keep in mind that including native plants in your mix is also important, since insects in your area may already recognize these local plants and have a preference for them. Check with your local extension agent to find what native plants are recommended for your area. Then include these common favorites in the mix (making sure to let them flower):
| Agastache | Catmint | Dill |
| Alyssum | Calendula | Echinacea |
| Bee Balm | Clover | Parsley |
| Borage | Coriander | Sage |
| Buckwheat | Cosmos | Thyme |
Related:
- 5 Early Season Plants That Attract Pollinators to Your Garden
- Bees Guided By Flowers’ Electric Fields
Plants that repel pests and diseases
Some plants produce compounds that help suppress the growth and development of other organisms in the garden. This process is known as allelopathy. A well-known plant with allelopathic properties is the marigold, which is known to reduce the presence of harmful nematodes in the soil. According to The Centre for Agriculture, Food, and Development, marigolds must first be grown and tilled into the soil before you plant if you want to get this benefit.
Other plants deter pests from munching on your crops simply because they smell or taste unfavorably. Examples include garlic, catnip, and chives discouraging Japanese beetles.
Here are some common favorites.
| Preferred Crop | Plants That Repel Pests |
|---|---|
| Tomatoes | Garlic, chives, and onions help to deter munching pests. Asparagus repels tomato nematodes. Borage repels tomato hornworm. Cilantro deters spider mites. |
| Cabbages, broccoli, kale (Brassica family) | Borage deters cabbage moth caterpillars. Garlic deters a multitude of pests due to its sulfur compounds. Cut mint spread around plants helps deter cabbage moths and aphids. Oregano used as mulch or interplanted serves the same purpose. Nasturtiums planted in an adjacent or nearby bed helps lure aphids away. Calendula produces a sticky substance that attracts and captures aphids. Marigolds deter cabbage maggots. Summer savory attracts honeybees and repels cabbage moths. |
| Potatoes | Catnip repels Colorado potato beetle. |
| Squash | Radishes planted in and around your squash plants will help repel a variety of pests including squash bugs. Gourds planted with sweet corn and beans will help deter squash vine borers. |
| Carrots | Clover planted in a carrot bed is said to repel wireworm. Basil, lettuce, nasturtium, and tansy are said to repel carrot rust fly. Members of the allium family (garlic, leeks, onions), along with some aromatic herbs (rosemary, sage) are also said to repel the rust fly. |
| Asparagus | Asparagus beetles dislike basil, calendula, nasturtium, parsley, tansy, and tomatoes. |
| Cucumbers | Onions and nasturtiums attract beneficial insects that will feed on cucumber beetles. |
Related:
- Natural Garden Pest Control Guide
- How to Create a Garden ‘Mini-Insectary’
Combinations that improve flavor
While this category is harder to test given its subjective nature, many gardeners swear by the following combinations including medicinal herbs, culinary herbs, and other plants.
- Thyme planted near strawberries is said to enhance flavor.
- Basil or cilantro planted in a tomato bed will improve the flavor of most varieties.
- Chamomile improves the flavor of onions when planted nearby.
- Chervil can add spiciness to radishes when planted in the same bed.
- Borage planted with strawberries is the favorite of many home gardeners.
Plants that improve soil nutrients
Adding clover, peas, or beans to any bed will help increase the nitrogen in your soil. That’s because these plants harbor bacteria in the nodules on their roots that help pull nitrogen from the atmosphere and convert it to a form useful to plants—both themselves and whatever else is planted near them.
Planting any of the following in a bed lacking nitrogen will improve this nutrient in the soil:
- Broad beans
- Bush beans
- Pole beans
- Dutch white or crimson clover
- Chick peas
- Snap, snow, or shelling peas
Planting buckwheat in a bed helps to add calcium to the soil. This is especially important if tomatoes have resided in that bed the year before, since tomatoes are heavy feeders of calcium.
You can also plant root crops apart so they don’t compete for phosphorous.
Related:
- 3 Useful Soil Mixes for Raised Garden Beds and Planters
- How to Build and Nourish Health Garden Soil
Plants that provide shelter
The following combinations of tall or vining plants and shade-loving plants can work together to provide improved growing conditions for both.
Lettuces and peas
Sow climbing peas early on a trellis oriented east-west. On the north side of the trellis, sow lettuce seeds. In the early part of the season when the peas are small, the lettuce will receive sunshine to warm the soil and speed germination. Once the peas are up and thriving, the lettuce will benefit from their shade as summer advances and the heat of the day threatens. This combination works well to extend your lettuce harvest and prevent premature bolting.
Broccoli and salad greens
As above, this combination can help shade lettuces, spinach, arugula, and other salad greens as summer advances and the large leaves of the broccoli plants expand to fill the space. Plant in alternating rows for the most benefit.
Related:
- How to Build a Bean Trellis for Raised Garden Beds
Combinations to avoid
In some cases, particular plants sown in close proximity will affect each other negatively. While the research on this is still developing, some common garden enemies identified by gardeners include:
- Garlic (and other alliums) with beans and peas
- Carrots with dill and other members of this family
- Cucumbers and fragrant herbs
- Spinach and potatoes
- Beets and pole beans
Top recommendations for raised garden beds
Over many years of gardening, we’ve made some observations of our own. Some of our favorites for pairings for raised garden beds include:
Tomatoes + onions/garlic + basil
Onions and garlic planted with tomatoes help to repel many common pests, including slugs and snails. Basil planted in the same bed can help enrich the flavor of ripe tomatoes.
Cabbage + radishes + marigolds
Radishes and marigolds planted with cabbages help control the cabbage maggots that commonly attack cabbage plant roots. Add some chives to this bed if you have a slug problem.
Lettuce + carrots + chives
Lettuce planted in and around carrots is known to repel carrot rust flies. Chives deter aphids and flea beetles from sucking the life out of your lettuce. They also help repel the carrot rust fly.
Squash + runner beans + corn
An old favorite known as the Three Sisters, this combination is a win-win-win. Squash benefits from interplanting with corn and beans, which deter common squash pests. Raccoons dislike the prickly squash vines, and will avoid them while leaving your corn alone. Runner beans flower, attracting pollinating insects to your squash, which need pollination to bear fruit. And finally, the corn acts as a natural trellis for those vining beans.
Kale + bush beans + beets
Another way of pairing plants is to consider which levels of the soil profile they occupy. While beets feed deeply in your garden, bush beans and kale have shallower roots and won’t present the same competition for nutrients as another root crop. They also add essential nutrients back to the soil and are harvested more quickly than beets. Be careful not to plant pole beans with beets, however, since these are known to be incompatible.
The best bedfellows
Whichever pairings you choose for your raised garden beds, make notes throughout the season on how it’s working in your unique space, under your garden’s specific set of conditions. If something isn’t working as well as it should, adjust as necessary with the knowledge that you’re taking part in an age-old practice.
